No. It's a noun (He is a leading tennis coach.) or verb (He will coach at the new tennis club.)
adjective
The word until can BEGIN an adverb clause, but it is not an adverb by itself. The word until is a preposition or conjunction.
The adverb clause typically modifies the verb in the sentence.
The clause 'that the coach recommended' may be an adjective clause, as it begins with a relative pronoun (that) and modifies a noun such as plan, or strategy, or program.(* It might also be part of a noun clause if used as the subject of a sentence, such as That the coach recommended a new plan seemed strange.)
subordinating conjunction
The relative pronoun who - it introduces adjective clauses, referring to a person.
The adverb clause is "when the moon is full." The subordinating conjunction is when, the subject is moon, and the verb is "is."
The underlined clause "when the race began" is an adverb clause modifying the adverb "novanent" in the sentence: "The runners increased their speed when the race began."
The sentence "She sings beautifully when she is happy" contains an adverb ("beautifully") that describes the verb "sings" in the noun clause "when she is happy."
An 'adverb clause' is a subordinate clause that modifies a verb, an adjective, or another adverb. It tells when, where, how, to what extent or under what conditions.
An adverb clause (adverbial clause) is a clause that describes a verb, adjective or adverb, in the same way that a single word, compound, or phrase acts as an adverb. They are subordinate clauses.Examples of adverb clauses:The boy laughed when the teacher's wig fell off.The bridge collapsed as the train rolled onto it.He is not awake until he has his first cup of coffee.
An embedded clause is not an adverb. It is a type of subordinate clause that is embedded within a main clause and functions as a noun, adjective, or adverb within the sentence.